FR3143438A1 - Motor vehicle comprising a device for fixing a lower arm to a cradle - Google Patents

Abstract

Motor vehicle (1) comprising a vehicle cradle (12) fixed to a chassis and extending transversely along a transverse axis (Y) and two lower arms (14) each comprising a first portion (15) for fixing to the cradle (12). ) and a second portion (16) for fixing to a wheel hub, the first fixing portion (15) extending along a longitudinal axis (X) perpendicular to the transverse axis (Y). The first portion (15) for fixing each of the lower arms (14) comprises a first fixing orifice (15b) extending along a vertical axis (Z) perpendicular to the longitudinal axis (X) and forming a first point of fixing (B) to the cradle (12). The fixing arm (14) comprising a second fixing hole (15a) extending along the longitudinal axis (X). The vehicle comprises at least one connecting device (20) configured to connect the second fixing hole (15a) of each lower arm (14) to the cradle (12). Figure for abstract: Fig. 3A

Description

Motor vehicle comprising a device for attaching a lower arm to a cradle

The present invention relates to the field of motor vehicles and in particular to the front axles of motor vehicles.

More particularly, the present invention relates to the fixing of the lower arms or bars of the front axle on the cradle of the motor vehicle.

The cradle of a motor vehicle is a metal part attached to the vehicle's chassis and located under the vehicle's engine. The cradle connects different parts of the engine, including the engine, shock absorbers, and fuel tank, to reduce the movement of these parts while the vehicle is moving.

Generally speaking, the front axle of a motor vehicle includes, on each side, a lower arm, bar or lower triangle of a suspension system which connects the cradle to the wheel hub, allowing in particular the attachment of a wheel spindle, a brake caliper and the connection with a universal joint.

The front axle also includes a suspension that connects the wheel hub to the vehicle body.

There illustrates a known example of a front part 1 of a motor vehicle comprising a cradle 2 extending transversely along a transverse axis Y and two lower arms 3, 4 each fixed to one end of the cradle 2.

The two lower arms 3, 4 are symmetrical. Only one of the lower arms 4 will be described later. The lower arm 4, here the right arm, comprises a first portion 5 for attachment to the cradle 2, extending along a longitudinal axis X and a second portion 6 for attachment to a wheel hub (not shown). The second attachment portion 6 extends along the transverse direction Y.

As illustrated in detail in Figures 2A and 2B, the first portion 5 for attachment to the cradle 2 comprises two attachment holes 5a, 5b to the cradle 2 extending along a vertical axis Z and each receiving first and second attachment means 7, 8, such as screws to form respectively a first and a second attachment point A, B to the cradle 2.

The second fixing portion 6 comprises a fixing orifice 5c extending along the vertical axis Z and receiving third fixing means (not shown), such as screws to form a third fixing point C to the wheel hub.

The length AB of the lower arm 4 corresponds to the distance between the front attachment of said arm 4 on the cradle 2 at point A and the rear attachment of said arm 4 on the cradle 2 at point B.

The width L of the lower arm 4 corresponds to the distance between the third attachment point C to the wheel hub and the segment AB connecting the two attachments A, B of the lower arm 4 on the cradle 2.

Reference may also be made to document US8100423-B2 which describes a lower arm for a motor vehicle suspension comprising an orifice for attachment to a wheel hub, a through orifice forming a first attachment to the cradle and a housing formed by metal sheets to form a second attachment to the cradle.

In order to widen the track of a vehicle, one could simply modify the transverse dimension of the cradle.

However, such a solution requires replacing the entire production line of the motor vehicle cradle.

Thus, there is a need to widen the track of a vehicle, that is, the overall width of the vehicle, without changing the transverse dimension of the cradle.

The aim of the invention is therefore to overcome these drawbacks and to propose a solution making it possible to widen the track of a vehicle, without modifying the transverse dimension of the cradle, while maintaining the ratio between the width and the length of each lower arm.

The present invention relates to a motor vehicle comprising a vehicle cradle fixed to a chassis and extending transversely along a transverse axis and two lower arms each comprising a first portion for fixing to the cradle and a second portion for fixing to a wheel hub. The first fixing portion extends along a longitudinal axis perpendicular to the transverse axis.

The first attachment portion of each of the lower arms comprises a first attachment hole to the cradle extending along a vertical axis perpendicular to the longitudinal axis and forming a first attachment point to the cradle.

The fixing arm comprises a second fixing hole extending along the longitudinal axis.

The vehicle includes at least one connecting device configured to connect the second attachment port of each lower arm to the cradle.

The connecting device allows the attachment point of the lower arm to the wheel to be offset in the transverse direction, without changing the dimensions of the cradle and the ratio between the width and length of the lower arm.

This makes it possible to widen the vehicle's track without changing the transverse dimension of the cradle, while maintaining the ratio between the width and length of each lower arm.

Advantageously, the connecting device comprises a connecting member comprising a main body extending along the vertical axis and comprising a vertical bore receiving first fixing elements, for example screws.

Said first fixing elements allow the fixing of the connecting device on the cradle to form a second fixing point to the cradle.

According to one embodiment, the connecting member further comprises at least one fixing lug extending from the main body in the transverse direction and comprising an orifice extending in the longitudinal direction and coaxial with the second fixing orifice of the lower arm, said orifices cooperating with second fixing elements, for example screws, to form an intermediate fixing point to the cradle.

Preferably, the first and second fixing elements are arranged in two perpendicular directions, namely the vertical direction for the first fixing elements and the longitudinal direction for the second fixing elements.

According to another embodiment, the connecting member comprises two fixing lugs extending parallel from the main body in the transverse direction, said parallel fixing lugs being axially spaced from each other by a longitudinal space for receiving the lower arm, in particular at the level of the second fixing orifice.

Advantageously, the connecting device further comprises a damping member arranged radially between the bore of the second fixing orifice of the lower arm and the second fixing elements.

The damping member of the connecting device makes it possible to obtain a front attachment of the lower arm to the cradle which is more flexible in the transverse direction and more rigid in the longitudinal direction, which has the advantage of controlling the opening angle of the front wheels when the vehicle is braking and in particular the positive angle known as the “toe-in” angle.

According to one embodiment, the damping member is integral with the lower arm and fixed inside the bore of the second fixing hole of said lower arm.

According to another embodiment, the connecting device further comprises a damping member integral with the connecting member.

Advantageously, the damping member is located radially in the orifice of the fixing lug and comprises a hole extending along the longitudinal axis over its entire length, coaxial with the orifice of the fixing lug and with the second fixing orifice of the lower arm in order to receive the second fixing elements, for example screws, to form the intermediate fixing point.

For example, the damping member and the fixing lug are integral with each other.

For example, the damping member is force-fitted into the hole in the mounting bracket. Alternatively, the mounting bracket is overmolded onto the damping member.

According to another variant, it could be provided that the damping member and the fixing lug form a single part.

Advantageously, the lower arm comprises two connecting tabs extending parallel from the main body of the lower arm in the transverse direction towards the connecting device. The two parallel connecting tabs are, for example, axially spaced from each other by a horizontal receiving space extending along the longitudinal axis for receiving the connecting device, and in particular the fixing tab.

Each of the connecting legs may comprise a through hole extending in the longitudinal direction. Said holes are coaxial with each other and with the hole in the damping member of the connecting device.

Said holes form the second fixing hole of the lower arm in order to receive second fixing elements, for example screws, to form the intermediate fixing point A1.

The diameter of the holes is, for example, greater than the diameter of the hole in the damping member of the connecting device.

According to yet another variant, it could be provided that the damping member is located radially in the vertical orifice of the main body of the connecting device.

For example, the damping member is made of elastically deformable material, configured to deform under the action of an external stress, and to return to its initial shape as soon as the external stress stops.

The damping element is, for example, made of rubber.

The second attachment portion of each lower arm comprises, for example, a attachment hole extending along the vertical axis and receiving third attachment means, such as screws, to form an attachment point to the wheel hub and intended to cooperate, for example, with a wheel hub.

Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely as a non-limiting example, and made with reference to the appended drawings in which:

very schematically illustrates part of the front axle of a motor vehicle according to the prior art;

shows in detail a point of attachment of a lower arm on the cradle of the vehicle of the ;

shows in detail a lower arm of the vehicle of the ;

shows in detail a device for connecting a lower arm to the cradle of a motor vehicle according to the invention;

shows in detail a lower arm of the vehicle of the ;

,
illustrate sectional views of the lower arm connecting device to the vehicle cradle according to the according to a first embodiment of the invention; and

,
illustrate sectional views of the lower arm to vehicle cradle connecting device of the vehicle according to the according to a second embodiment of the invention.

In the following description, the terms "longitudinal", "transverse", "vertical", "front", "rear", "left" and "right" are defined according to the usual orthogonal reference of motor vehicles, shown in the drawings, and which includes:

- a longitudinal axis X, horizontal and oriented from the front to the rear of the vehicle;

- a transverse axis Y, horizontal, perpendicular to the longitudinal axis X and oriented from the left to the right of the vehicle when the vehicle is moving;

- a vertical axis Z, orthogonal to the longitudinal and transverse axes X and Y and directed from bottom to top.

In the remainder of the description, reference is made to the front part 1 of the motor vehicle described with reference to the . The front part 1 of the vehicle comprises, in a known manner, a cradle extending transversely along a transverse axis Y and two lower arms each fixed to one end of the cradle.

The two lower arms are symmetrical.

On the , the fixing of one of the lower arms 14 on a cradle 12 of the motor vehicle by means of a connecting device 20 is shown very schematically.

The attachment of the other lower arm being symmetrical, it will not be described later.

As illustrated in detail on the , the lower arm 14, here the right arm, comprises a first portion 15 for attachment to the cradle 12, extending in a longitudinal direction X and a second portion 16 for attachment to a wheel hub (not shown). The second attachment portion 16 extends in a transverse direction Y.

The first portion 15 for attachment to the cradle 12 comprises a first attachment orifice 15b extending along a vertical axis Z and receiving first attachment means (not shown) to the cradle 12, such as screws to form a first attachment point B to the cradle 12.

The lower arm 14 comprises a second fixing orifice 15a extending along a longitudinal axis X, here horizontal, perpendicular to the vertical axis Z.

As illustrated in the , the second fixing hole 15a is located at the junction between the first portion 15 for fixing to the cradle 12 and the second portion 16 for fixing to a wheel hub.

The second fixing hole 15a forms an intermediate fixing point A1.

The motor vehicle 1 further comprises a connecting device 20 connecting the lower arm 14 to the cradle 12, and in particular the second fixing orifice 15a.

The second fixing portion 16 comprises a third fixing orifice 15c extending along the vertical axis Z and receiving third fixing means (not shown), such as screws to form a fixing point C to a wheel hub (not shown).

As illustrated in detail in FIGS. 4A and 4B, the connecting device 20 comprises a connecting member 22 comprising a main body 24 extending along the vertical axis Z and comprising a vertical bore 24a receiving first fixing elements 17, for example screws for fixing to the cradle 12.

The connecting member 22 further comprises two fixing lugs 26, 27 extending parallel from the main body 24 in the transverse direction Y towards the lower arm 14. The two parallel fixing lugs 26, 27 are spaced axially from each other by a horizontal receiving space (not referenced) extending along the longitudinal axis X for receiving the lower arm 14.

Each of the fixing legs 26, 27 comprises a through hole 26a, 27a extending in the longitudinal direction X.

The orifices 26a, 27a are coaxial with each other and with the second fixing orifice 15a of the lower arm 14 in order to receive second fixing elements 18, for example screws, to form the intermediate fixing point A1.

The first and second fixing elements 17, 18 are arranged in two perpendicular directions, namely the vertical direction Z for the first fixing elements 17 and the longitudinal direction X for the second fixing elements 18.

The connecting device 20 further comprises a damping member 28 mounted radially between the bore of the second fixing orifice 15a of the lower arm 14 and the second fixing elements 18.

The damping member 28 comprises a hole 28a extending along the longitudinal axis X over its entire length, coaxial with the orifices 26a, 27a of the fixing lugs 26, 27 and with the second fixing orifice 15a of the lower arm 14 in order to receive the second fixing elements 18, for example screws, to form the intermediate fixing point A1.

The respective diameter of the orifices 26a, 27a of the fixing lugs 26, 27 of the connecting device 20 is here greater than the diameter of the hole 28a of the damping member 28.

In the example illustrated in detail in FIGS. 4A and 4B, the damping member 28 is integral with the lower arm 14 and fixed inside the bore of the second fixing orifice 15a of the lower arm 14.

Alternatively, as illustrated in FIGS. 5A and 5B, the damping member 28 is integral with the connecting member 22.

In this case, the connecting member 22 comprises only one fixing lug 26 extending in projection from the main body 24 in the transverse direction Y.

As illustrated in FIGS. 5A and 5B, the connecting device 20 further comprises a damping member 28 located radially in the orifice 26a of the fixing lug 26.

The damping member 28 and the fixing lug 26 are integral with each other.

For example, the damping member 28 is force-fitted into the orifice 26a of the fixing lug 26. Alternatively, the fixing lug 26 is overmolded onto the damping member 28.

According to another variant, it could be provided that the damping member 28 and the fixing lug 26 form a single part.

The damping member 28 comprises a hole 28a extending along the longitudinal axis X over its entire length, coaxial with the orifice 26a of the fixing lug 26 and with the second fixing orifice 15a of the lower arm 14 in order to receive the second fixing elements 18, for example screws, to form the intermediate fixing point A1.

In the example illustrated in detail in Figures 5A and 5B, the damping member 28 is integral with the connecting device 20.

As illustrated in FIGS. 5A and 5B, the lower arm 14 comprises two connecting tabs 14a, 14b extending parallel from the main body of the lower arm 14 in the transverse direction Y towards the connecting device 20. The two parallel connecting tabs 14a, 14b are spaced axially from each other by a horizontal receiving space (not referenced) extending along the longitudinal axis X for receiving the connecting device 20, and in particular the fixing tab 26.

Each of the connecting legs 14a, 14b comprises a through hole 14c, 14d extending in the longitudinal direction X.

Said orifices 14c, 14d are coaxial with each other and with the hole 28a of the damping member 28 of the connecting device 20.

Said orifices 14c, 14d form the second fixing orifice 15a of the lower arm 14 in order to receive second fixing elements 18, for example screws, to form the intermediate fixing point A1.

The diameter of the orifices 14c, 14d is here greater than the diameter of the hole 28a of the damping member 28 of the connecting device 20.

According to yet another variant (not shown), it could be provided that the damping member 28 is located radially in the vertical orifice 24a of the main body 24 of the connecting device 20. Generally, the damping member 28 is made of elastically deformable material, configured to deform under the action of an external stress, and to return to its initial shape as soon as the external stress stops.

The damping member 28 is, for example, made of rubber.

Thanks to the invention, it is possible to widen the vehicle track, without modifying the transverse dimension of the cradle, while maintaining the ratio between the width and the length of each lower arm.

In fact, the connecting device 20 makes it possible to shift the attachment point C of the lower arm 14 to the wheel in the transverse direction Y, without modifying the dimensions of the cradle 12 and the ratio between the width and the length of the lower arm 14.

Furthermore, the connecting device 20 according to the invention allows the front attachment 15a of the lower arm 14 to the cradle 12 to be more flexible in the transverse direction Y and stiffer in the longitudinal direction X, which has the advantage of controlling the opening angle of the front wheels when braking the vehicle and in particular the positive angle known as the “toe-in” angle.

Claims (10)

Motor vehicle (1) comprising a vehicle cradle (12) fixed to a chassis and extending transversely along a transverse axis (Y) and two lower arms (14) each comprising a first portion (15) for fixing to the cradle (12) and a second portion (16) for fixing to a wheel hub, the first fixing portion (15) extending along a longitudinal axis (X) perpendicular to the transverse axis (Y), the first fixing portion (15) of each of the lower arms (14) comprising a first fixing orifice (15b) to the cradle (12) extending along a vertical axis (Z) perpendicular to the longitudinal axis (X) and forming a first fixing point (B) to the cradle (12), and the fixing arm (14) comprising a second fixing orifice (15a) extending along the longitudinal axis (X), characterized in that the vehicle comprises at least one connecting device (20) configured to connect the second fixing hole (15a) of each lower arm (14) to the cradle (12). Vehicle (1) according to claim 1, in which the connecting device (20) comprises a connecting member (22) comprising a main body (24) extending along the vertical axis (Z) perpendicular to the longitudinal axis (X) and comprising a vertical bore (24a) receiving first fixing elements (17) for fixing to the cradle (12). Vehicle (1) according to claim 2, wherein the connecting member (22) further comprises at least one fixing lug (26, 27) extending from the main body (24) in the transverse direction (Y) and comprising an orifice (26a, 27a) extending in the longitudinal direction (X) and coaxial with the second fixing orifice (15a) of the lower arm (14), said orifices (26a, 27a, 15a) cooperating with second fixing elements (18) to form an intermediate fixing point (A1) to the cradle (12). Vehicle (1) according to claims 2 and 3, in which the first and second fixing elements (17, 18) are arranged in two perpendicular directions (X, Y). Vehicle (1) according to claim 3 or 4, in which the connecting member (22) comprises two fixing lugs (26, 27) extending parallel from the main body (24) in the transverse direction (Y), said parallel fixing lugs (26, 27) being axially spaced from each other by a longitudinal space for receiving the lower arm (14). Vehicle (1) according to any one of the preceding claims, in which the connecting device (20) further comprises a damping member (28) arranged radially between the bore of the second fixing orifice (15a) of the lower arm (14) and the second fixing elements (18). Vehicle (1) according to claim 6, in which the damping member (28) is integral with the lower arm (14) and fixed inside the bore of the second fixing orifice (15a) of said lower arm (14). Vehicle (1) according to claim 3 or 4, in which the connecting device (20) further comprises a damping member (28) integral with the connecting member (22). Vehicle (1) according to claim 8 in combination with claim 3, wherein the damping member (28) is located radially in the orifice (26a) of the fixing lug (26) and comprises a hole (28a) extending along the longitudinal axis (X) over its entire length, coaxial with the orifice (26a) of the fixing lug (26) and with the second fixing orifice (15a) of the lower arm (14) in order to receive the second fixing elements (18) to form the intermediate fixing point (A1). Vehicle (1) according to any one of the preceding claims, in which the second attachment portion (16) of each lower arm (14) comprises a attachment orifice (15c) extending along the vertical axis (Z) and receiving third attachment means to form an attachment point (C) to the wheel hub.